Sheet feeder



Nov. 17, 1936. H. EHREG ET AL SHEET FEEDER Filed Jan. 6, 1936 3Sheets-Sheet 1 A rromvsy Nov. 17, 1936. H. EHRIG ET AL SHEET FEEDERFiled Jan. 6, 1936 5 Sheets-Sheet 2 ,N VE N TOIQ S; 16/15 155/ 9, mm44/7004 Arromvey H. EHRIG ET A]- S HEET FEEDER Filed Jan. 6, 1936 sSheets-Sheet a Nov, 17, 1936.

Patented Nov. 17, 1936 UNITED STATES PATENT OFFICE SHEET FEEDER HansEhrig and Ulrich Keilhauer, Leipzig,

Germany Application January 6, 1936, Serial No. 57,655 In GermanyDecember 6, 1935 8 Claims. (01. all-as) feeding sheets or blanks ofpaper, cardboard, metal foil, and like flexible materials, piled up on atable, to the presses concerned.

The principal object of the invention is to provide a structurallyimproved sheet feeder, which will be of greater and more universalserviceability in the printing and allied trades, viz. which can be putin action to advantage for a greater variety of printing jobs and otherwork than sheet feeders knownheretofore.

This and various other objects aimed at by our invention and theadvantages obtained will be more fully understood by the reader afterhaving critically reviewed the working characteristics of the two mainclasses of sheet feeders known in the trade:viz. of feeders, hereinafterbriefly called dashers, by which the sheets are singly transferred tothe press as seen in Fig. 1 of the accompanying drawings, viz. beingdashed forward one behind the other-in spaced relation-to eachother;-and sheet feeders for staggered feed, hereinafter briefly called"staggerers, by which the sheets are conveyed to the press in staggeredposition to each other, viz. in the form of a continuous row of sheetsoverlapping each other to a large extent as seen in Fig. 2.

As a matter of fact known to practitioners dasher feeders have a widerrange of application than staggerers, inasmuch as a great variety ofdifferent printing jobs can be carried out therewith.

' Besides carrying out jobs, wherein the sheets under treatment arestill in virgin, unprinted condition, sheets, which are to be reprinted,having gone already through the press and received imprints, can besafely transferred to the press with dasher feeders, without incurringthe risk of smearing, setting off and afllicting like damages to thesheets in transit.

In addition thereto bydasher feeders sheets of paper forchromolithographic, artistic and kindred purposes can be safely fedhaving polished,

' calendered, chalked and glazed surfaces of a delicate, highlysensitive nature, and which must be Lil safeguarded against beingrubbed, shuflled or otherwise brought into frictional contact with eachother.

Dasher feeders however have the disadvantage, that their output isrelatively low, since the speed, at which the sheets are ultimatelydashed forward to the front lay marks of the feed .table must be keptbelow certain limits because of the risk of buckling and tearing thefront edge of sheets on striking against said front lay marks.Notwithstanding the provision of slowing-down gears in dasher feedersfor retarding the sheets 5 in transit immediately before reaching thefront lay marks only a maximum number not exceeding 3-5000 sheets perhour can be safely transferred in practice by dasher feeders to thepress consistent with the size, weight, pliability and 10 other physicalproperties of the paper, of which the sheets consist.

Since printing and other presses usually can be run faster than at therate of 3-5000 sheets per hour the output of presses fitted with-dasherfeed- 5 ers is in fact curtailed by technical imperfections of thosefeeders, which means, that the production costs of the printing jobscarried out therewith are higher than they should be.

In contradistinction thereto with feeders for staggered feed, referredto above, in which every first sheet in transit, viz. that, whichapproaches the front lay marks and is the nearest thereto needs to. beultimately advanced only through a relatively short distance so as toreach the latter, a larger number of sheets can safely be fed, averaging5-7000 sheets per hour, consistent with their size, weight, pliability,etc.

However feeders for staggered feed (Fig. 2)

cannot be used for the reasons indicated above 30 in those many cases,where the sheets are to be reprinted as in multicolor printing, orpresent relatively large areas covered with imprints in bold type, madewith plenty of printing ink, or

in which the sheets have surfaces of a delicate 35 nature indicatedhereinbefore, and must not come into frictional, rubbing or shuttlingcontact with each other in transit to the press.

The invention aimsat providing a structurally improved sheet feeder,which presents the ad- 40 vantages of both classes of feeders, describedabove, namely which can be converted at a moments notice from a dasherfeeder into a staggerer and vice versa.

In connection therewith the invention aims at so redesigning the sheetfeeder concerned, that certain drawbacks occurring with feeders of theaforedescribed classes and being known as stoppers or misfeedings areeliminatedzto the press in a reliable, trouble free manner,

and without necessitating tiresome, or time consuming readjustments,conversions, etc.

For this purpose self-adjusting, suction operated actuating means areprovided for gently tilting upwardly the sheet separating primarygrippers and in such manner, that no "creeping will occur at theupper-most sheets of the pile, which would impair the correctregistering of the sheets at the front lay marks.

Another important feature of the re-designed feeder is the provision ofsuction operated secondary gripping means for stretching the separatedsheets in lateral direction, while they are further advanced anddelivered to the sheet conveyor proper.

Still other objects aimed at by the invention will become incidentallyapparent hereinafter to practitioners in this field.

The nature and scope of this invention are briefiy outlined in theappended claims and will be more fully understood from the followingspecification taken together with the accompanying drawings, in which:

Figs. 1-2 are fragmentary side elevations diagrammatically showing byway of an example a sheet feeder improved according to this invention;in Fig. 1 the feeder is set for dashing i. e. transferring the sheetssingly and spaced from each other to the press, while Fig. 2 shows thefeeder re-set for staggered feed;

Fig. 3 diagrammatically shows the path of movements of the primary andsecondary grippers, cooperatively associated according to this inventionfor separating the sheets from the pile,

stretching them in lateral direction and delivering same to theconveyor;

Fig. 4 is a plan appertaining to Figs. 1 and 2;

Figs. 5-8 are diagrammatic lay-outs showing different characteristicpositions of the sheet separating means;

Figs. 9-10 are side elevations drawn in a larger scale and showing someimportant structural details of the primary grippers and the suctionoperated means provided for upwardly tilting same;

Fig. 1-1 is a front view of said primary grippers and their tiltingmeans;

Fig. 12 is a front view showing two of the sheet delivering secondarygrippers, and the suction actuated means for laterally stretching thesheet intransit;

Fig. 13 is a cross section through one of the sheet delivering andstretching grippers.

With the objects in view stated hereinbefore the sheet feederre-designed according to this invention and shown by way of an examplein the drawings essentially consists of (A) A device for separating thesheets from a pile, lifting and advancing them in the feeding direction;

(B) A sheet conveyor, which transfers the separated sheets to the pressand is provided according to this invention with two sets of actuatingmeans adapted to work the conveyor at the operators option alternativelyat two different rates of speed.

A. Sheet separating device The sheets are separated by two sets ofsuction operated grippers-hereinafter called primary grippers IO-lll,and secondary grippers 20-20, 2l2l', 22--22', and by means of an airblast tube having nozzles, which are diagrammatically indicated at P, P.r

The said primary grippers l0, l, while being at rest in their initialposition shown in Fig. 1 engage the sheets near their front edge and arethen tilted upwardly about their rear edge 1 (Fig. 9-10) by improvedtilting means, which are also suction operated, whereupon the saidgrippers HI, ID are moved by their actuating means in the direction ofarrows c--c2 in a closed path of movements seen in dot and dash lines inFig. 3, until they reach again their initial position; while thegrippers l0, l0 pass point i the sheet in transit is disengagedtherefrom and is re-engaged first by the outside grippers 2020' of thesecondary set, which will immediately stretch the sheet in lateraldirection, as indicated in dash lines in Fig. 12, whereupon the othergrippers 2l 2l', 22-22 of the secondary set join in by also engaging thesheet and advance the latter in the direction of arrow e (Fig. 3)towards the sheet conveyor; the sheet being disengaged .at point 11 andin turn re-engaged by the rollers 34, 35 of the conveyor referred tohereinafter.

Air under reduced pressure briefly called suction air is supplied froman air pump or a storage tank to the primary grippers l0, l0 throughrubber tubes L3, L4, which are guided by rollers R, R (Figs. 9-10) theadmission and cutting-off of the suction air being controlled by camactuated valves or equivalent air distributing means of known design(not shown). air is supplied to the grippers 20-20', 2l2l', 2222 of thesecondary set.

The mechanism for moving the grippers of the primary set along the pathindicated by a dot and dash line in Fig. 3 comprises: (1) a couple ofhook shaped arms ll, (2) pitmans l2, which are linked to said arms H andare slidingly guided and supported at their forked front ends by arotary driving shaft 10, driven from shaft 80; (3) levers l3 linked tosaid arms H and fulcrumed at 3a; (4) pins l2, l3 projecting from saidpitmans l2 and levers l3 respectively and being cooperatively engaged bycovered cams (not shown), which are formed within a rotary disk l4 keyedto the driving shaft 10.

The mechanism for moving the grippers 20-2D', 2|-2l', 22-22 of thesecondary set along the path indicated by a dash line in Fig. 3comprises: 1) two pairs of angular arms 21, (2) double cranked levers 28linked to said arms 21 and fulcrumed at M, (3) pins 21, 28' projectingfrom arms 21 and levers 28 respectively and being cooperatively engagedby covered cams (not shown), which are formed within rotary disks 29,29' (Fig.4) keyed to the driving shaft ID.

A structurally improved tilting mechanism operated by suction airisprovided for the purposes of this invention for tilting the primarygrippers I0, 10 around their rear edges rr' on engaging the top sheet ofthe pile S. Said tilting mechanism comprises: (1) air cylinders I5, l,which are in communication with the atmosphere at 5a and are connectedat 50 with tubes L, L2 leading to the suction air distributing means(not shown) referred to above; (2) spring loaded pistons 5i slidablyfitted in said cylinders and being responsive to suction air propagatingtherein as seen in Fig. 10, (3) pin and slot gears I 6 of arc shape,which are formed at the upper ends of arms II for guiding the grippersl0, l0 during their tilting motion, the center of the arcs concernedbeing at r-r'; (4) bell crank levers l1 and links l8, l9 interconnectingsaid pistons 52 and grippers l0, l0.

Likewise suction One of the outstanding advantages derivedfrom operatingthe above describedtilting mechanism indirectly by suction air insteadof by directly and positively acting power transmitters lies therein,that the improved tilting mechanism is self-adjusting: Sheets differingin their thickness and pliability-e. g. tissue paper as against thickand stout paper-are differently, namely, individually treated during thetilting action: Since the total power transmitted from the pistons 51'and available at the grippers I0, 10 for upwardly folding the frontedges of the sheets is in all cases practically the same the grippersI0, ID are tilted through a smaller angle-approximately 2030-in the caseof sheets of stout paper than in the case of thinner papers being undertreatment, where the tilting angle will be about 30-40.

Another advantage lies in the fact that, in all cases ample time isgiven to the grippers l0, I for settling upon, firmly engaging bysuction and upwardly folding the sheets to be separated;-

thus avoiding misfeedings, which are often due to insuflicient timebeing given to the grippers for settling upon and securely engaging bysuction the sheets, when the pressand its feeder run at high rates ofspeed; in other words a noteworthy feature consists in the grippers I0,10' being declutchcd or emancipated during their settling, engaging andtilting action from any directly or positively acting driving elementsof the feeder and being meanwhile practically independent of the workingspeed of the latter.

As explained above the sheets separated and lifted by the primarygrippers l0, l0 are disengaged therefrom and reengaged ati (Fig. 3)first by the grippers 20-20' of the secondary set in order to belaterally stretched. The stretching mechanism with which the grippers20-20' are structurally associated according to this invention is alsosuction operated and comprises: (1) air cylinders 25-45, which are incommunication with the atmosphere at 511 and to which suction air issupplied at e through rubber tubes and a distributing device of knowndesign (not shown); (2) spring loaded pistons 5n, which are responsiveto suction air propagating in said cylinders, and to which the grippers20, 20' are attached; the nozzles of the latter being in communicationwith the cylinders 25, 25' through channels 21',

The sheets in transit on being engaged near their lateral edges by thegrippers 20-20' (Fig. 7) are simultaneously stretched as indicated indotted lines in Fig. 12 and are thereupon engaged also by the grippers2l--2l', 22-22 for being delivered in flattened condition to B. Thesheet conveyor and out of operation at the operator's option.

The said power transmission gears comprise: (1) aniaxle 60; (2) sprocketwheels 40-50 journalled thereon and being connected by chains withcorresponding sprocket wheels 42-52 attached to drum 30; (3) ellipticspur wheels "-5! journalled on axle 60 and locked with the sprocketwheels 40--50; (4) elliptic spur wheels 43-53 journalled on the rotaryshaft and being slotted for cooperation with grooved and toothedclutches ll-l2, which are geared by means of key and slot gears Ia-1cwith the rotary shaft 10; (5) double armed levers 13-44 engaging saidcouplings ll-12 and being operated by a connecting rod having a handle18.

The ratios of gearing of said chain drives are so chosen, that, whenclutch ll engages spur wheel 43 the sheets are carried forward singlyand spaced from each other as with da'sher-feeders (Fig. 1) while, whenclutch I2 is in operation as seen in Fig. 4 the sheets will overlap eachother as in feeders for staggered feed (Fig. 2) referred to at length inthe preamble of this specification.

Instead of the said elliptic spur wheels 4l--43, 5I53 other variablespeed gears or equivalent slowing down mechanisms may be convenientlyused for retarding the sheets on approaching the front lay marks.

Various other changes and modifications may be made in the structuraldetails of sheet feeders of the improved design described hereinbeforewithout deviating from the spirit and the salient ideas of thisinvention.

For instance in addition to the hand operated connecting rod 15 aself-acting electromagnetically operated control mechanism may beprovided for throwing out of operation the respective clutches H or 12in case of misfeeding.

The chain drive 40-42 may be dispensed with altogether, where the pressconcerned is designed for staggered feed only.

Obviously the total number of the grippers provided for the primary andsecondary set may be varied, namely chosen consistent with the maximumwidth of the sheets for which the feeder is built.

What we claim is:

1. In a sheet feeder for printing presses, ruling, folding and likemachines the combination with means for separating the sheets from apile, of means for conveying the separated sheets to the press, saidseparating means comprising two sets of grippers, a primary and asecondary one, which are cooperatively arranged at the front-end of thepile of sheets, the grippers of the primary set being adapted to engagethe sheets from above and being provided with means for being tilted andmoved in a closed cycle of movements, so as to separate, lift andadvance the sheets in the feeding direction, the grippers of thesecondary set being adapted to subsequently engage the sheets fromunderneath and being provided with means for laterally stretching thesheets and for being moved in a closed cycle of movements soas tofurther advance and deliver the sheets to the conveying means.

2. In a sheet feeder for printing presses, ruling, folding and likemachines the combination with means for separatirfi the sheets from apile, of. means for conveying the separated sheets to the press, saidseparating means comprising two sets of grippers, a primary and asecondary one, which are cooperatively arranged at the front end of thepile of sheets, the grippers of theprimary set being adapted to engagethe sheets from above and being provided with means for being tilted andmoved in a closed cycle of movements,

so as to separate, lift and advance the sheets in the sheets fromunderneath and being provided with means for laterally stretching thesheets and for being moved in a closed cycle of movements so as tofurther advance and deliver the sheets to the conveying means-and meansprovided at the front end of the pile of sheets for blowing airthereunder in the direction opposite to the feeding direction.

3. In a sheet feeder for printing presses, ruling, folding and likemachines the combination with 'means for separating the sheets from apile, of means for conveying the separated sheets to the press,.saidseparating means comprising two sets of grippers, a primary and asecondary one, which are cooperatively arranged at the front end of thepile of sheets, the grippers of the primary set being adapted to engagethe sheets from above and being provided with means for being tilted andmoved in a closed cycle of movements, so as to separate, lift andadvance the sheets in the feeding direction,- the grippers of thesecondary set being adapted to subsequently engage the sheets fromunderneath and being provided with means for laterally stretching thesheets and for being moved in a closed cycle of movements so as tofurther advance and deliver the sheets to the conveying means-saidtilting means being suction operated and comprising cylinders, springloaded pistons slidably fitted therein and being responsive to suctionair propagating within said cylinders, arc shaped pin and slot gears forguiding the grippers of the primary set during their tilting motion andmeans for cooperatively interconnecting said grippers and pistons.

4. In a sheet feeder for printing presses, ruling, folding and likemachines the combination with means for separating the sheets from apile, of means for conveying the separated sheets to the press, saidseparating means comprising two sets of grippers, a primary and asecondary one, which are cooperatively arranged at the front end of thepile of sheets, the grippers of the primary set being adapted to engagethe sheets from above and being provided with means for being tilted andmoved in a closed cycle of movements, so as to separate, lift andadvance the sheets in the feeding direction, the grippers of thesecondary set being adapted to subsequently engage the sheets fromunderneath and being provided with means for laterally stretching thesheets and for being moved in a closed cycle of movements so as tofurther advance and deliver the sheets to the conveying means-saidtilting means being suction operated and comprising cylinders, springloaded pistons slidably fitted therein and being responsive to suctionair propagating within said cylinders, are shaped pin and slot gears forguiding the g ppers of the primary set during their tilting motion andmeans for cooperatively interconnecting said grippers and pistons,-thecenter of thearc of said are shaped pin and slot gear being located atthe rear edges of the grippers of the primary set.

5. In a sheet feeder for printing presses, ruling, folding and likemachines the combination with means for separating the sheets from a.pile, of means for conveying the separated sheets to the press, saidseparating means comprising two sets of grippers, a primary and asecondary one, which are cooperatively arranged at the front end of thepile of sheets, the rippers of the primary set being adapted to engagethe sheets from above and being provided with means for being tilted andmoved in a closed cycle of movements,

so as to separate, lift and advance the sheets in the feeding direction,the grippers of the secondary set being adapted to subsequently engagethe sheets from underneath and being provided with means for laterallystretching the sheets and for being moved in a closed cycle of movementsso as to further advance and deliver the sheets to the conveyingmeans,said means for stretching the sheets being suction operated andcomprising two cylinders, spring loaded pistons, which are slidablyfitted therein so as to be responsive to suction air propagating withinsaid cylinders, and to which two of the grippers of the secondary setare attached viz. those which are nearest to the lateral edges of thesheets.

6. In a sheet feeder for printing presses, ruling, folding and likemachines the combination with means for separating the sheets from apile, of means for conveying the separated sheets to the press, saidseparating means comprising two sets of grippers, a primary and asecondary one, which are cooperatively arranged at the front end of thepile of sheets, the grippers of the primary set being adapted to engagethe sheets from above and being provided with means for being tilted andmoved in a closed cycle of movements, so as to separate, lift andadvance the sheets in the feeding direction,'the grippers of thesecondary set being adapted to subsequently engage the sheets fromunderneath and being provided with means for laterally stretching thesheets and for being moved in a closed cycle of movements so as tofurther advance and deliver the sheets to the conveying means-saidconveying 'means being double geared, viz. provided with two powertransmission gears difiering from each other in their ratio of gearing,and with coupling means for reciprocally throwing those gears into andout of operation, their respective ratio of gearing being so chosen,that the separated sheets are conveyed to the press either singly andspaced from each other, or collectively in the form of a row of sheetsoverlapping each other.

7. In a sheet feeder for printing presses, ruling, folding and likemachines the combination with means for separating the sheets from apile, of means for conveying the separated sheets to the press, saidseparating means comprising two sets of grippers, a primary and asecondary one, which are cooperatively arranged at the front end of thepile of sheets, the grippers of the primary set being adapted to engagethe sheets from above and being provided with means for being tilted andmoved in a closed cycle of movements, so as to separate, lift andadvance the sheets in the feeding direction, the grippers of thesecondary set being adapted to subsequently engage the sheets fromunderneath and being provided with means for laterally stretching thesheets and for being moved in a closed cycle of movements so as tofurther advance and deliver the sheets to the conveying means,-'-saidconveying means being double geared viz. provided with two powertransmission gears differing from each other in their ratio of gearing,and with coupling means for reciprocally throwing those gears into andout of operation, their respective ratio of gearing being so chosen,that the separated sheets are con veyed to the press either singly andspaced from each other, or collectively in the form of a row of sheetsoverlapping each other,said coupling means comprising a main drivingshaft and two releasable clutches cooperatively associated with saidshaft and the said power transmission gears.

8. In a sheet feeder for printing presses, ruling, folding and likemachines the combination with means for separating the sheets from apile, of means for conveying the separated sheets to the press-saidconveying means being double geared viz. provided with two powertransmission gears differing from each other in their ratio of gearing,and with coupling means for reciprocally throwing those gears into andout of operation, their respective ratio of gearing being so chosen,that the separated sheets are conveyed to the press either singly andspaced from each other, or collectively in the form of a row of sheetsover-- lapping each other. I g

' HANS EHRIG.

ULRICH KEJLHAUER.

